is there an escape character for envsubst?

Question

Is there a way to prevent envsubst from substituting a $VARIABLE? For example, I would expect something like:

export THIS=THAT
echo         


        

Answer 1

If there's only one or two variables you don't want to expand, you can sort of whitelist them by temporarily setting them to their own name, like this:

$ echo 'one $two three $four' | four='$four' envsubst
one  three $four

Here, the $four variable gets replaced with $four, effectively leaving it unchanged.